Bill shock is becoming an epidemic in Australia, with a new report finding many consumers spend 50 per cent more than expected each month on mobile phone calls.
Analysing more than 200 mobile phone bills, a Macquarie University report - The Anatomy of Bill Shock: An Analysis of Mobile Phone User Experience in Australia 2012 - examined the cause and effect of bill shock, which costs approximately $557 million.
The study found that 55 per cent of women were affected by bill shock as opposed to 45 per cent of men, getting stung calling premium and overseas numbers.
Men, however, are more likely to spend about 14 per cent more than women in downloading data.
Worst affected are 25-to-39-year-olds, who spend on average $37.76 in monthly phone plan excess charges.
The study also revealed Australia's most popular mobile plane price point of $59 had the highest incidence of bill shock.
Macquarie University marketing lecturer David Gray said the concept of "included value" in mobile plans need to be more clearly communicated to consumers.
"Recent changes adopted by the industry since this bill analysis are a step in the right direction, but the bills we've viewed even in the past few weeks still left us scratching our heads," Dr Gray said.